I have a USB DAC device and Audio MIDI Setup lists several possible options for configuring its output.

Format can be set as any of 11 different settings, ranging from 4990 Hz to 55010 Hz, with 2 channel 8 bit, 2 channel 16 bit or 2 channel 20 bit options. I'm playing ALAC files through iTunes. What settings should I choose?

Thanks in advance.

Which Mac? Which OS? Which USB DAC device? What's the DAC connected to? How is it connected?

If you're mainly playing Apple lossless, and no higher res files, start with 44.1 KHz and 2 ch-16 bit.

24-inch iMac, Intel Core 2 Duo, OS X 10.4.11. The device is the Xitel Hifi USB Link, connected via its analog stereo output to a Marantz integrated amp.

It's a stopgap device as I am looking for a DAC to use with the iMac's optical output.